Time To Live, denoted as TTL, is a critical concept within the DNS framework that dictates the “shelf life” of a DNS record in caching systems. When a DNS resolver fetches a record, it doesn’t keep referring to the original server for every subsequent request. Instead, it caches this record. The TTL value, expressed in seconds, indicates how long this record is valid before a fresh lookup is mandated. This mechanism is crucial for efficient network performance. Shorter TTLs ensure updated records are fetched faster, whereas longer TTLs reduce the overhead of frequent DNS lookups. Check out a more detailed explanation of what TTL is.